Drill.



G. F. HEINKEL & J. MUTH.

DRILL.

APPLICATION FILED 001. 24, 190B.

Patented Apr. 2, 1912.

UNITED STATES PATENT OFFICE.

CHRISTIAN r. HEIATKEL AND'JOHN MUTE, or CLEVELAND, omo; sAIi) mum ASSIGNOR 'ro sen) HEINKEL.

DRILL.

Specification of Letters Patent.

Patented Apr. 2, 1912.

To all whom it may concern:

Be it known that we, CHRISTIAN F. HEINKEL and JOHN MUTH, citizens of the United States, residing at, Cleveland, in the county of Cuyahoga and State of Ohio, have invented anew and useful Improvement in Drills, of which the following is a specificatlon.

Our invention relates to drills in which one or more cutters are molecularly united to a body.

The object of our invention is to produce a drill which does not break easily and which is economical of manufacture.

We attain our object by molecularly uniting one or more cutters of suitable material to. a body of softer and more flexible and cheaper material.

It is well known in the art that drills, as heretofore made, are easily broken, particularly the high-speed drills and, being made of higher-priced material throughout, are more expensive of manufacture than the drills of our invention. With our invention,

the cutters only are made of higher-priced material while thebody is made of softer and cheaper material, .thereby reducing cost of manufacture and mitigating breakage.

Our invention is sufliciently illustrated in the accompanying drawing in which; a

Figure I is a general side-view of a twist drill with one cutter and lubrication-tubes.

,Fig. II is a section on line XX of Fig. I,

general side-vlew of a twist-drill, on a smaller scale and showing an increasing twist.

Similar reference-characters refer to similar parts throughout the several views.

v Figs. I,,II, and III of said drawing represent a twist-drill which is composed, principally, of a body 1 and a cutter 2.

In carrying out our invention we prefer to construct body 1 of a rather soft and flexible material, such as machinerysteel, wrought-iron, steel casting, malleable-iron, bronze, brass, or even cast-iron if not too brittle, and provide on said body a suit-- able shank 3. When body 1 is made of commercial bar stock, we prefer to cut the spiral flutes 4 into body l by the usual milling operation, which operation also produces slit 5 automatically since no material is left there after flutes 4: are cut; a section of a body with flutes so cut will appear as Fig. III. For the purpose of strength of'the twist-drill shown, the faces 8 of spiral flutes 4: are made straight. The leading faces 9 of spiral flutes 4 should be made straight so that cutter 2 may be united thereto readily. Further details for flutes 4. will appear hereinafter in connection with description of cutter 2. Grooves 6 may be cut into body 1 and lubrication-tubes 7 may be secured therein by soldering or other suitable means.

Cutter 2 is, preferably, made of highspeed steel, but may be made of a material suitable for general or special work. It will be seen (Fig. II) that cutter 2 extends across the diameter of the drill and fills slit 5 and lies against faces 9. When cutting flutes 4, faces 9 are cut sufficiently deep so that cutter 2 can lie snugly against faces 9 as is clearly shown in Fig. II. For the purpose of providing the proper cutting angle on the drill, cutter 2 is twisted by means of.dies, rolls or other similanmeans well known in the art. Said twist ma be a constant twist as seen in Figs. I and II, or an increasing twist as seen in Fig. VIII; these different twists being well known in the art. The spiral or twist of flutes 4, hereinbefore described, should conform to the twist of cutter 2 so that cutter 2 lies snugly agalnst faces 9, crosswise (Fig. II) as well as lengthwise (Fig. I). For the purpose of grinding or otherwise finally finishmgthe drill-to size, we prefer to first form cutter 2 somewhat wider than the diameter to which the drill is to be finished. Cutter 2 may be hardened before or after molecular unition with body 1. i

In some methods of molecular unition, as for instance in brazing or casting, the harnot be used in such case.

dening of cutter 2 and molecular unition of body 1 and cutter 2may be accomplished at one operation and with one heating, as will appear hereinafter.

Aft-er cutter 2 is properly prepared it is inserted into slit 5 and molecularly united to leading faces 9 of flutes 4. Said molecular unition may be accomplished by means of' soldering, brazing, welding, casting, or a combination of said means. All of said methodsof molecular unition, as well as others, are well known in the a'rt'and may be employed with suitable modifications; no detailed description thereof is thought necessary here.- It may be well to state here,

however, that, when casting body 1 to cutter Y We, generally, prefer to place cutter 2 into a suitable m'old before said cutter is hardened and, after pouring the molten body-material into said mold, leave the drill in said mold sufficiently long to absorb suflicientheat from said molten material forproperhardening of cutter 2. The drill is then removed from said mbld and cooled by a suitable cooling means whereby said cutter is suitably hardened. Cutter2 may also be hardened before being placed into said mold and a chill placed over said cutter to prevent annealing. When casting body 1 to cutter 2 of small drills, we, generally, prefer to harden said cutter before the casting operation since the molten material in such small body may not contain suflicient heat to properly heat said cutter for hardening; a chill may or may When casting body 1 to cutter 2 of a small drill and when said cutter is made of high-speed steel, we

prefer to harden said cutter before the casting operation and employ a chill if necessary to prevent annealing of cutter 2.

i When, however, said cutter is made of carbon steel and the molten body-material contains sufficient heat to harden said cutter, We prefer to harden said cutter by means of the heat from the molten material as hereinbefore described and draw the temper on said cutter by another operation; when the molten body -'material contains insufficient heat for hardening of said carbon steel cutter, we prefer to harden said cutter before the casting operation and draw the temper on said cutter either before said casting op-- eration, or during said casting operation by means of the heat of the molten material, or

- after said cast-ing operation by another heating operation. The material in the body of a larger drill generally, imparts suflicient heat to the cutter for proper hardening so that casting of body and hardening ofscutter may be accomplished at one operation and without any additional heating, thus reducing cost of manufacture. The procedure, best adapted to any particular case must be judged by the quantityof molten body-material and any one skilled in the art should be able to select the proper procedure from the general descriptions given herein.

When cutter 2 is united to body 1 by means other than casting, brazing for instance, cutter 2 becomes heated and may be heated sufliciently for hardening, thus uniting body 1 and cutter 2 and hardening cutter 2 with one heating and: reducing cost of manufacture. After body l and cutter 2 are united, cutter 2 is hardened if'it was not hardened previous to, or during unition to bodyl. The drill may now be finally finished by grinding or otherwise.

Figs. IV, V, andVI of said drawing represent a straight-fluted drill with a plfirality of cutters and is composed, -principally, of

body 10 and cutters 11 and 12.

In carrying out our invention, we prefer to construct-body 10 of material similar to body 1 hereinbefore described and provide thereon a suitable shank 13. Flutes 14 and 15 are provided on body 10 either by cutting, or casting, or forging, similar to flutes 4. Body 10 has two deepflutes 14, a slit which connects said deep flutes and which is adapted to receive cutter 11: The faces 16' of flutes 14 may have any suitable contour, but should have as large a cross-sectional area as possible, so as to provide the necessary chip-room. The leadingfaces 17 of flutes lt'are, straight and adapted to re'- ceive cutter 111, similar to faces 9 'hereinbefore described. The faces 18 of flutes 15, may have any suitable contour, but shouldhave as large-an area as possible to provide chip-room. Jll he leading faces 19 of flutes 15 are straight and adaptedto receive cutters 12. Cutter 11 is, in this instance, a flat strip .of suitable material, a little wider than the diameter of the finished drill, similar to cutter 2 hereinbefore described, and adapted to be molecularly'united to the leading faces 17. Cutters 12 are flat strips of suitable material adapted to be molecularly united to the leading faces 19. We prefer to provide an undercut seat 21 (Fig. TY) for cutters 12 which seat aids to hold said cutters in place both during and after 'molecular unition with body 10.

The operations of hardening cutters 11 body 10 and molecular unition of said cutters to said body are similar to the correand 12 as well as the methods of forming the twist-drill hereinbefore described.

Forsmaller drills we prefer toprovide one cutter only (Figs I and II) which extends centrally across the diameter of the I body, has two cutting-faces, and determines the size of the drill. For larger drills we prefer to provide a plurality of cutters, as for instance Figs. V and VI, so that material may be removed more rapidly, or in other words, a drill with a plurality of cutters will do more work in a giventime than a drill with one cutter. Providing'more than one cutter on small drills is not ractical mechanicall The cutters of these drills may exten along the entire length of the fluted portion of the body as seen in Figs. I and IV, or fluted portion as for mstance the cutter 20 of Fig. VII.

It is obvious that a twist-drill can be constructed with a plurality of cutters, a crossconstructed with one cutter, 'a cross-section of which will appear as Fig. II. The drawing shows, for the purpose of clearly illus- :trating, a twist-drill with one cutter and a straight-fluted drill with four cutting-edges andthree cutters, but we do not limit ourselves to such construction only.

1 breakage.

. structed of so It will be noted that we use a comparatively small amount of the higher-priced material in our drills, the body, being the larger part of the drill, is constructed of cheaper material, thus saving considerably on cost of material.

A further advantagewehave with our invention is that our drills do not break as easily as those constructed entirely of steel poses. The bod of our drill, being conand flexible material, strengthens and supports the cutter, or cutters and renders the drill less. liable to Our cutter or cutters, being of part way along said uniform size throughout, have more flexibility than a drill which is constructed of one piece and which has a non-uniform cross-section. a v

Whereas this is an application for anarticle and descri tions of detail-steps as to process of manuihcture are unnecessary, and whereas many processes or methods may be emiloyed to construct an article which embo ms our invention, we have, hereinbefore,

given a methods vention.

general outline only of several 0 manufacture adapted to our in- The outline of methods so described should, however, enable any one skilled in the art to construct an. article which embodies our invention, either by the methods as described, or by said methods with suitable modifications, or by othermethods adapted to produce an article of our invention. ,We claim:

1. A drill having a body a shank onsaid a body, two flutes in said body, a slit connecting said flutes, and a cutter in said slit and molecularly'united to the leading faces of said flutes.

2. A drill having a body, a shank on said body, a plurality of flutes in said body, a slit connecting two of said flutes, one cutter in said] slit and molecularly united to the leading faces of said two flutes, and a plurality of cutters molecularly united to the leading faces of the others of. said flutes.

3. A drill having a body, 'a shank on said body, a lurality of flutes in said body, two of said utes deeper than the others of said flutes and connected by a slit, one cutter in said slit and molecularly united to the leading faces of said deeper flutes and extending across the diameter of said drill, and a plurality of narrower cutters molecularly united to the leading faces of the others of said flutes.

\ CHRISTIAN F. HEINKEL.

' JOHN MUTH.

Witnesses HENRY R. SYDON, F mm: S. SMITH. 

